FIGURE 7.

E2F1 protein is dispensable for Rb binding to both the E2F1 binding site and the TAAC element. A, the 2BS cells expressing vector alone (Ctrl) or a combination of H-Ras and vector control, shRNA against E2F1 (shE2F1), Rb (shRb), or HMGA1 (shHMGA1) were assessed for BrdU incorporation and SAHF formation. The values represent the means and standard errors for three independent experiments. B, the 2BS cells expressing vectors alone (G) or a combination of H-Ras and vector control (S) shRNA against E2F1 (S/shE2F1) were processed for ChIP using anti-HP1γ, anti-H3K9Me3, and anti-Rb antibodies or using nuclear extract (input) or IgG as a negative control. The primer sets used for CSIG-T, PCNA-T, and CCNA2-T include the CSIG/PCNA/CCNA2 promoter regions containing the TAAC element. Ctrl, control.